Tube forming



April 11, 1950 B. BANNISTER I ma F'omnc 4 Shoots-Sheet 1 Filed Oct. 12, 1944 [5 lib/Way B. B'ANNISTER was romlmc April 11, 1950 4 Sheets-Sheet 3 Filed 001;. 12, 1944 bweizlar:

April 11, 1950 a. BA'NNISTER TUBE FORIING 4 Sheetshoot 4 Filed Oct. 13, 1944" bwenlor: @fiemwr LZfl/V/V/ETEE, & 6 di /army.

Patented Apr. 11, 1950 UNI STATES TUBE FORMING Bryant Bannister, Pittsburgh, Pa, asslgnor to National Tube Company, a corporation of New Jersey Application October 12, 1944, Serial No. 558,361

12 Claims. 1

This invention relates to tube forming and, more particularly, to reducing the diameter tubing without increasing the wall thickness thereof or if desired simultaneously reducing the wall thickness and diameter.

In the present method of tube forming or tapering, a tube is subjected to controlled tension or stretching action to control the wall thickness thereof while the diameter is being reduced by a set of planetary rolls. In order to have a uniform and controlled temperature, the tube or workpiece is heated by an electric induction heater immediately prior to its being contacted by the reducing rolls. Thus, the length of the finished workpiece is limited by the apparatus or forming equipment rather than the temperature drop occurring in conventional hot working, wherein the workpiece is removed from a furnace and exposed to atmospheric cooling while being worked. 4

It is accordingly an object of the present invention to form tubing having a uniform or varying diameter, and a uniform or varying wall thickness.

It is another object of the present invention to provide apparatus for hot reducing tubing in a closely controlled manner.

The foregoing and further objects will be a arent from the specification and drawings wherein: I

Figures 1, 2, 3, 4 and 5 are side elevations showing the sequence of operations in forming tubes in accordance with my invention;

Figure 6 is a side elevation of the roll carriage and roll cluster;

Figure 7 is a cross section on lines VII--VII of Figure 6;

Figure 8 is an end view of the roll cluster assembly, partly in section;

Figure 9 is a view similar to Figure 6 but partly in section;

Figure 10 is a sectional view of a workpiece and the connector members;

Figure 11 is an isometric view of the carriage cylinder; and

Figure 12 is a similar view of the tube tension cylinder and speed controlling arrangement.

Referring more particularly to the drawings, the numeral I designates a pair of suitably elevated tubular tracks rigidly supported by a series of posts 2. A roll carriage 3 is adapted for rolling travel along tubular tracks I on profiled carriage wheels 4 and a piston rod carriage 5 moves thereon on profiled wheels 6.

Angularly disposed with respect to carriage wheels 4 are flat faced rollers 4* located at forward and rearward end of carriage 3, and properly positioned for lateral contact with tracks I, thus precluding any lateral deflection of carriage 3 during longitudinal movement along tracks I.

Longitudinally aligned and at a lower elevation than tracks I is a. firmly mounted fluid cylinder 7, piston (not shown) and piston rod 9, the piston rod a being in engagement with downwardly eiztending member 9 of roll carriage 3 whereby car riage 3 may be moved in either direction on tracks i by actuation of the piston in cylinder i. longitudinally opposed and in same longitudinal vertical plane as carriage cylinder i, but at a higher elevation, and in same horizontal plane as workpiece and roll cluster, hereinafter described, is a rigidly mounted tension cylinder it, piston (not shown) and piston rod it connected to carriage 5 whereby controlled movement oi carriage 5 in either direction along tracks 0 may be efi'ected.

Rigidly and longitudinally centrally mounted on frame of roll carriage 3 is a roll drive motor H, to the armature shaft of which is fixed multiple belt sheave i 3 connected by belts I 4 to complementary multiple belt sheave i5. sheave IB is keyed to end of hollow spindle l6, mounted in anti-friction bearings it contained within bearing housing It and mating cans is, which are attached to frame of roll carriage 3. To opposite end of hollow spindle is from sheave I5 is at tached cluster roll housing 20 by means oi threaded joint 2! whereby said cluster roll housing 20 is adapted to rotate with hollow spindle i 6. Completely surrounding and keyed for longitudinal sliding engagement and rotation with neck of cluster roll housing is longitudinal drive ring 22 journaled in anti-friction bearing 28 in turn contained within circular bearing housing 24 and cap 25. Circular bearing housing 24 and cap 25 are retained in non-rotative position by means of vertical links 26, in engagement with trunnions 21 suitably positioned upon and integral with circular bearing housing 25. The vertical links 26 are pivotally connected at the lower ends thereof to horizontal short links 28 which are, in turn, pivotally connected at opposite ends to bottom of frame of roll carriage 3 as shown at 29. Top of vertical links 26 are drilled to receive crosshead 30 extending inwardly for engagement with horizontal short links 3!, the other ends 01' which span and are pivotally connected to eye 32 integral with piston rod 33 emanating from piston (not shown) enclosed within power cylinder 34 securely and longitudinally centrally located on base plate 35 which is securely-attached to spindle bearing housing l8. By means of this linkage, activation of power cylinder 34 for piston movement in either direction will translate such motion to move drive ring 22 longitudinally of the hollow spindle IS in the same direction as the piston.

Uniformly and radially spaced within cluster roll housing 20 are three roll cartridge assemblies 35 which have double flanges 38 adjacent the outer ends and which are inwardly keyed to cluster roll housing, as shown at 31, for movement radially thereof in counterbores 38 in the cluster roll housing 20. Counterbores 38 have shoulders 33" whereby contact with lower cartridge flanges 36 precludes further movement radially inwardly and suitable caps 39 whereby cartridges 35 are positively contained within the cluster roll housing 25. Contained within cartridges 35 are suitable anti-friction radial and thrust bearings for satisfactory support of roll shafts 40 on the downward end of which are mounted suitably profiled rolls 4|.

Uniformly and radially spaced about the drive side of roll cluster housing 20 are three slots 42, each slot being radially spanned by pairs of bored lugs 43 suitably spaced to receive bell cranks 44 pivotally mounted between the bored lugs 43. The bell cranks 4 are so designed that one end engages a peripheral slot 2i in longitudinal drive ring 22 and the other end passes through slots 42 in cluster roll housing 20 and engages periph- I eral slots 42 in roll cartridges formed between aforementioned double flanges 36. Thus, movement imparted to the longitudinal drive ring 22 by means of control cylinder 34 through linkage hereinbefore described will arcuately move bell cranks 44 to effect an 'inwardly or outwardly radial movement of roll cartridge assemblies to vary the pass opening formed by the rolls whereby any desired diameter may be formed on a tubular workpiece.

Centrally located on roll carriage 3 immediately adjacent cluster roll assembly is a high frequency induction coil heater 45, tubular in cross section. suitable for receiving a. portion of tubular workpiece and raising its temperature for forging immediately thereafter by action of the rolls.

Suitably mounted and rigidly held at carriage cylinder end of mill is a longitudinally extending i rod 46 disposed on the center line of mill and similarly disposed but longitudinallyopposed in piston rod extendin through piston rod support carriage 5. Inward ends of both rod 46 and tension cylinder piston rod ii are adapted for receiving and gripping a workpiece X between them by means of connector pieces 48 and thereby maintain any desired degree of tension on workpiece K through tension cylinder i5. Connector pieces 48 are designed for threaded engagement at one end with internal screw threads 41 of the workpiece X and the opposite end has a tongue 5| for reception in a slot 52 at the end of rods 45 and ii. Pins 53 are inserted through aligned holes 54 in tongues 5| and rods 46 and Connector pieces 48 are designed to be threaded into workpiece X before presentation to mill. Adapting to mill then consists merely of entering tongues 5| into slots 52 and securing Joints by entering pins 53 therein.

Figure 11 shows an hydraulic system for controlling operation of the mill. In this hydraulic system, controls of tension and roll positioning cylinders are both operated as a function of the movement of piston rod carriage 5, movement of which, due to elongation of workpiece resulting from roll and tension action, operates cams and valves as hereinafter described.

Attached to piston rod carriage 5 is a movable rack 55 engaging gear 56 affixed to gear shaft 51, suitably journaled and positioned in bearings (not shown). Also aflixed to gear shaft 51, above and below gear 55, are cam rack gears 59 and in mesh with cam racks 6| and 62, respectively, to which are rigidly afflxed profiled cams 63 and 64. Suitably positioned and retained for enment with profiled cams 53 and 64 are cam followers 65 and 56 carrying cam follower racks 51 and 68 which are in mesh with valve stem gears 61 and 65 afllxed to stems of tension cylinderand roll positioning cylinder control valves 55 and 15, respectively.

The inner end of the tension cylinder I0 is connected to a source of high pressure fluid by line 1| through a 3-way valve 12 havin an exhaust line 30. Inc outer end of the cylinder in is connected to a source of low pressure through line 14 and 3-way valve 13, and exhausting of the fluid therefrom to line 8| is controlled by valve 59.

The inner end 11 of the roll positioning cylinder 34 is connected to a source of fluid under low pressure to constantly urge the rolls to their largest opening and the opposite end is connected to a source of high pressure by line 15 through control valve 10 and 3-way valve 15 provided with an exhaust line 32.

Both ends of carriage positioning cylinder 1 are alternatively connected to a source of fluid under low pressure by line 13 and to a drain by line 83 by 4-way valve 13.

In operation, the roll carriage 3 is positioned at the extreme carriage cylinder and of the travel as shown in Figures 1 and 2 by admitting low pressure fluid to the inner end of cylinder 1 by 4-way valve 18, thereby exposing the forward end of the rod 45 at the inner end of the hollow spindle iii of roll carriage 3. One end of the workpiece X, which has connector pieces 48 screwed into both ends thereof, is then secured to the end of the rod 46 and the piston rod carriage is moved to the proper position by shutting off the inner end of the cylinder ill from the high pressure line 1| and opening it to the exhaust line by 3-way valve 12 and admitting low pressure to the outer end of the cylinder III by 3-way valve 13. The other end of the workpiece X is then secured to the piston rod The roll carriage 3 is then moved to the position shown in Figure 3 toward the tension cylinder end of the mill by admitting fluid under pressure by 4-way valve 18 to the outer end of carriage positioning cylinder 1 until the induction heater 45 surrounds the end portion of the workpiece X adjacent the tension cylinder end of-the mill. The coil is then energized and, as soon as the end portion of the workpiece X has obtained the proper temperature, the motor I2 is started to revolve the cluster roll assembly 25 in a planetary motion around the workpiece and low pressure fluid is admitted by 4-way valve 18 to the inner end of carriage positionin cylinder 1. At the same time, tension of a predetermined magnitude is applied to workpiece X by means of constant high pressure line 1| through 3-way valve 12 and thence to the ,inlet of tension cylinder ID, the piston movement 'of which is controlled by the limited flow of fluid from the outlet end of the cylinder, such limitation being effected by means of tension cylinder control valve 53. Thus, as reducing operation begins, original tension applied effects movement of piston rod carriage 5 to the right on drawing, with consequent similar movement of rack 55. This in turn moves profiled face of cam 53 compelling follower 55 to follow said profile whereby cam follower rack 61 is similarly moved and rotates gear 61- affixed to the stem of tension cylinder control valve 53 in such manner as to increase outflow velocity of fluid from cylinder due to greater increase in length of the workpiece X, as cross section thereof becomes smaller. In this manner. action of tension cylinder in is accurately controlled by means of proper cam profile to prevent thickening of the walls of the tube during the diameter reduction or to produce a tapering wall thickness as desired.

Roll positioning cylinder 34 is likewise activated hydraulically by means of high pressure line 15 and controlled by means of roll positioning cylinder control valve it which is activated by cam 64, suitably profiled for control desired. The profiled cam N is positioned by movement of piston rod carriage through rack 55 in identical manner as hereinbefore described for operation of tension cylinder control valve 69. As shown, the cam is profiled to produce a constant taper on the O. D. of the workpiece but it is obvious that by changing the profile, a tube having a constant or varying diameter asdesired can be produced.

Upon completion of the tube tapering opera tion and subsequent removal of finished tube from mill, the tension cylinder piston must be returned to starting position for connection with next workpiece. This is accomplished by manipulation of 3-way valve it; simultaneously with simliar 3-way valve "i2. Valve 13 is operated to admit fluid from low pressure line 14 to rear end of cylinder while valve 12 is positioned to block. high pressure line ii and open front end of cylinder to drain thus allowing return movement of tension cylinder piston activated by low pressure line it.

Reverse action or opening of rolls by means of roll positioning cylinder 36 is accomplished by operation of 3 way valve it to close high pressure line it and open the outer end of the cylinder to the exhaust line 82. This permits the low pressure which is constantly applied to the opposite end ll of the cylinder 34 to move the piston towards the outer end and return the rolls to the original open position. During the operating or closing cycle of the rolls, pressure exerted on other end of cylinder from high pressure line 15 is sumcient to overcome such resistance and thereby produce desired inward movement of rolls.

While I have shown and described one specific embodiment of my invention, it will be understood that this embodiment is merely for the purpose of illustration and description and that various other forms may be devised within the scope of my invention, as defined in the appended claims.

I claim:

1. Apparatus of the class described which comprises means for holding a tubular workpiece, means for heating a short section of the workpiece held thereby neans closely adjacent said heating means for reducing the heated workpiece, said reducing means comprising a plurality of rolls, means for rotating said rolls about the axis of the workpiece, means for moving said rolls longitudinally of the workpiece, additional means for applying tension to the workpiece, means for varying the opening between said rolls during rotation thereof and means for varying said tension while a workpiece is being reduced to obtain a tube having the desired diameter and wall thickness.

:2. Apparatus for reducing tubing which oomprises means for holding a tubular workpiece against rotation, means for heating a short section of the workpiece held thereby, a hollow spindle surrounding said workpiece closely adjacent said heating means, said spindle being rotatively mounted, a plurality of cone-shaped rolls defining a rolling pass mounted on said spindle and adapted to rotate therewith to reduce the heated section of the workpiece, means for rotating said spindle, means for moving said spindle longitudinally of the workpiece, additional means for applying tension to the workpiece throughout the length thereof, and means for varying the opening between said rolls during rotation thereof and means for varying said tension while a workpiece is being. reduced to obtain a tube having the desired diameter and Wall thickness.

3. Apparatus for reducing tubing which comprises means for holding a tubular workpiece against rotation, a carriage adapted to move longitudinally of the workpiece, a rotatable hollow spindle carried by said carriage surrounding the workpiece, means on said carriage and closely adjacent said spindle for heating a short section of a workpiece, a housing mounted on said spindle and adapted to rotate therewith, a plurality of rolls defining a rolling pass mounted in said housing and adapted to be rotated by engagement with the workpiece to reduce the heated section of the workpiece, said rolls being adjustable transversely of said spindle to vary the pass formed thereby, means for rotating said spindle, means for varying the opening between said rolls, additional means for applying tension to the work-= piece, and means for varying said tension and the adjustment of said rolls while a workpiece is being reduced to obtain a tube having the desired diameter and wall thickness.

4. Apparatus for reducing tubing which comprises means for holding a tubular workpiece against rotation, a carriage adapted to move longitudinally of the workpiece, means for heating asection of the workpiece carried thereby, a rotatable hollow spindle on said carriage surrounding the workpiece, a housing mounted on said spindle and adapted to rotate therewith, a plurality of rolls defining a rolling pass mounted in said housing and adapted to be rotated by engagement with the workpiece, said rolls being slidably mounted in said housing for adjustment transversely of said spindle, a sleeve slidably mounted on said spindle, a plurality of hell cranks pivotally mounted on said housing and having operative connection with said rolls and said sleeve whereby movement of said sleeve will vary the opening between said rolls, and means for moving said sleeve.

5. Apparatus for reducing tubing which comprises means for holding a tubular workpiece against rotation, a carriage adapted to move longitudinally of the workpiece, means for heating a section of the workpiece carried thereby, a rotatable hollow spindle on said carriage surrounding the workpiece, a housing mounted on said spindle and adapted to rotate therewith, a plurality of rolls defining a rolling pass-mounted in said housing and adapted to be rotated by engagement with the workpiece, said rolls being slidably mounted in said housing for adjustment transversely of "said spindle, a sleeve slidably mounted on said spindle, a plurality of bell cranks pivotally mounted on said housing and having operative connection with said rolls and said I sleeve whereby movement of said sleeve will vary the opening between said rolls, means for moving said sleeve, means for applying tension to the workpiece, and means for varying said tension.

6. Apparatus for reducing tubing which comprises means for holding a tubular workpiece against rotation, a carriage adapted to move longitudinally of the workpiece, a rotatable hollow spindle on said carriage surrounding the work= a 7 piece, a housing mounted on said spindle and adapted to rotate therewith, a plurality of rolls defining a rolling pass mounted in said housing. and adapted to be rotated by engagement with the workpiece, said rolls being slidably mounted in said housing for adjustment transversely of said spindle, a sleeve slidably mounted on said 7 spindle, a plurality of hell cranks pivotally mounted on said housing and having operative connection with said rolls and said sleeve whereby movement of said sleeve will vary the opening between said rolls, and means for moving said sleeve.

7. Apparatus for reducing tubing which comprises means for holding a tubular workpiece against rotation, a carriage adapted to move longitudinally of the workpiece. a rotatable hollow spindle on said carriage surrounding the workpiece, a housing mounted on said spindle and adapted to rotate therewith, a plurality of rolls defining a rolling pass mounted in said housing and adapted to be rotated by engagement with the workpiece, said rolls being slidably mounted in said housing for adjustment transversely of said spindle, a sleeve slidably mounted on said spindle, a plurality of hell cranks pivotally mounted on said housing and having operative connection with said rolls and said sleeve whereby movement of said sleeve will vary the opening between said rolls, means for moving said sleeve, means for applying tension to the workpiece, and means for varying said tension.

8. Apparatus of the class described which comprises means for holding a tubular workpiece, means for heating a short section of the workpiece held thereby, means adjacent said heating means for reducing the heated workpiece, said reducing means comprising a plurality of rolls, means for revolving said rolls about the axis of the workpiece, said rolls being transversely adjustable during rotation thereof to vary the opening therebetween, means for applying tension to the workpiece, means for moving said rolls longitudinally of the workpiece and means responsive to the reduction of the workpiece to control the opening between said rolls and the amount of tension applied to the workpiece to obtain a tube having the desired diameter and wall thickness.

9. Apparatus for reducing tubing which comprises means for holding a tubular workpiece against rotation, means for heating a short sectionof the workpiece held thereby, a hollow spindle surrounding said workpiece, said spindle being rotatably mounted, a plurality of coneshaped rolls defining a rolling pass mounted on said spindle and adapted to rotate therewith to reduce the heatedsection oi the workpiece, means for rotating said spindle, said rolls being transversely adjustable during rotation thereof to vary the opening therebetween, means for app ying tension to the workpiece, means for moving rolls deilning a rolling pass mountedin said housing and adapted to be rotated by engagement with the workpiece, said rolls being adjustable transversely of said spindle during rotation there of to vary the pass formed thereby, means for rotating said spindle, means for applying tension to the workpiece and means responsive to the reduction of the workpiece to control the transverse adjustment of said rolls and the amount of tension applied to the workpiece to obtain a tube having the desired diameter and wall thickness.

11. Apparatus for reducing tubing which comprises means for holding a tubular workpiece against rotation, a carriage adapted to move longitudinally of the workpiece, a rotatable hollow spindle on said carriage surrounding the workpiece, a housing mounted on said spindle and adapted to rotate therewith, a plurality of rolls defining a rolling pass mounted in said housing and adapted to be rotated by engagement with the workpiece, said rolls being slidably mounted in said housing for adjustment transversely oi said spindle during rotation thereof, a sleeve slidabl mounted on said spindle, a plurality of bell cranks pivotally mounted on said housing and having operative connection with said rolls and said sleeve whereby movement of said sleeve will vary the opening between said rolls, means for applying tension to the workpiece and means responsive to the reduction of the workpiece to move said sleeve to control the transverse adjustment of said rolls and the amount of tension applied to the workpiece to obtain a tube having the desired diameter and wall thickness.

12. Apparatus for reducing tubing which comprises means for holding a tubular workpiece against rotation, means for applying tension to the workpiece, a rotatable hollow spindle surrounding the workpiece, means for causing relative longitudinal movement between said spindle and the workpiece, means closely adjacent said spindle for heating a short section of the workpiece, a housing mounted on said spindle and adapted to rotate therewith, a plurality of rolls defining a rolling pass mounted in said housing and adapted to be rotated by engagement with the workpiece to reduce the heated section of the workpiece, said rolls being adjustable transversely of said spindle to vary the pass formed thereby,

means for rotating said spindle, means for varying the opening between said rolls, additional means for varying said tension and the adjustsaid spindle longitudinally of the workpiece and means responsive to the reduction-oi the work-'- piece to control the opening between said rolls and the amount of tension applied to the workpiece to obtain a tube having the desired diameter and wall thickness.

10. Apparatus for reducing tubing which comprises means for holding a tubular workpiece against rotation, a carriage adapted to move longitudinally of the workpiece, a rotatable hollow spindle carried by said carriage surrounding the workpiece, a housing mounted on said spindle and adapted to rotate therewith, a plurality of ment of said rolls while a workpiece is being reduced' to obtain a tube having a desired diameter and wall thickness.

BRYANT BANNISTER.

REFERENCES orrEo The following references are of record in the the of this patent:

UNITED STATES PATENTS Number Name Date 166,449 Blakey Aug. 10, 1875 573,873 Harris Dec. 29, 1896 582,472 Hesse May 11, 1897 1,318,962 Brinkman Oct. 14, 1919 1,618,515 Coryell Feb. 22, 192"! FOREIGN PATENTS Number Country Date 3,510 Great Britain of 1910 420,485 Great Britain Dec. 3, 1934 

